Method of treating petroleum oils containing sulphur



Dec.'9, 1930. G. J. ZISER ET AL 1,734,215

METHOD OF TREATING PETROLEUM OILS CONTAINING SULPHUR Filed Jan. 9/1926 I g m v g a F P E E E E a E s I I w Patented Dec. 9, 1930 UNITED STATES PATENT OFFICE GEORGE J. ZISER, OF LO$ ANGELES, AND JAMES H. OSMER, 015 EL SEGUNDO, CALI- FORNIA, ASSIGNORS, BY MESNE ASSIGNMENTS, TO STANDARD OIL COMPANY OF cnmroama, or SAN FRANCISCO,

CALIFORNIA, A CORPORATION OF DELAWARE METHOD OF TREATING PETROLEUM OILS CONTAINING SULPHUR Application filed January 9, 1926. Serial No. 30,156.

This invention relates to a process of treating petroleum oils, and particularly distillates which have been obtained from crude oils containing relatively high percentages of sulphur compounds. The invention refers particularl to the treatment of gasoline and kerosene o tained from naphthenic crudes which have a relatively high sulphur content. The invention is applicable to the normal straight run distillates of such crudes as well as to cracked distillates or distillates derived by supplying such crudes to pressure distillation operation. Such oils are very difiicult to refine by present known methods.

The distillates obtained from the above described crude oils are not suitable for marketing without refinement, due to the pres ence of sulphur compounds which impart a disagreeable odor and cause the products to darken upon standing in storage. The presence of the deleterious compounds which cause such darkening is determined by the well known doctor test. A gasoline containing compounds which react positively to the doctor test is said to be sour and'the process of removing these sulphur compounds is termed sweetening. A gasoline which causes a negative doctor test is said to be sweet.

' The present methods of sweetening gasoline comprises the treatment of the gasoline with sulphuric acid in quantities and strength proper to remove the objectionable compounds; also treatment with sodium plumbite; and more recently hypochlorite of soda has been employed for sweetening distillate. 'p

There are certain objections to each of the above described methods, and the object of,

the present invention is to provide a method for sweetening distillates of petroleum oils which is free from the objectionable features of the present methods. The main objection to the acid treatment is the loss in distillate due to the polymerizing action of the sulphuric acid on certain of the constituents of the gasoline which are desirable in the The plumbite treatment generally requires that the distillate, after treatment, should be redistilled to free the finished product from the sodium plumbite reaction products. The

.hypochlorite method of treatment also normally requires a re-distillation or re-running for the formation of a proper finished product.

By the method of the present invention the following objects are accomplished.

present refinery equipment without necessitating expensive changes.

(6) The distillate subsequent to treatment does not have to'be re-run.

(7 An entire elimination of the necessity for acid treatment on the lighter varieties of motor fuel; and

(8) A sweetening of highly unsaturated cracked motor fuel or naptha without great polymerization losses due to acid treatment.

We have discovered that salts of copper when dissolved in water and properly commingled with a distillate in the presence of oxygen will remove the objectionable sulphur compounds and leave a sweetened product and give the negative doctor test. For the supply of oxygen, air has been found to be satisfactory. The particular salt of coper which has proven most effective is that obtained when copper sulphate is dissolved in water and ammonium hydroxide is added until the first precipitate formed is'dissolved,

and the characteristic deep blue color due to the complex copper ammomum ion is ob-.

carriers of the atmospheric oxygen. The result of the treatment is probably oxidation of the unstable sulphur compounds which are thereby changed either to a water soluble form and are removed from the distillate as such or are stabilized so that they will no longer act positively towards the doctor test.

Various further objects and advantages of our present invention will be more readily understood by reference to the accompanying drawings which illustrate diagrammatically an apparatus suitable for carrying out the present invention.

The drawing discloses a diagrammatic view of a suitable petroleum oil treating apparatus.

In the drawings 1 represents a storage tank for the copper salt solution to be employed and 2 and 3 represent different agitating tanks. 4 is a tank for the spent copper salt solution such as spent copper ammonia solution, and 5 is a tank for receiving the finished or treated stock.

With such apparatus the required amount of copper ammonia solution is removed from the tank 1 by a pump 7 into the agitator 2, the solution passing through line 8. Simultaneously the untreated distillate of petroleum oil is passed through pipe 10 from a source of supply (not shown) into the agitator 2. The distillate and treating solution enter the agitator through a spray 12, valves 6, 9 and 11 being employed to control the rate of addition of the copper ammonia solution and distillate, and valve 32 being closed. The distillate and treating solution are thus thoroughly commingled and pass into the agitator 2 in the form of a fine spray. Within the agitator 2 the liquid level is preferably maintained about-half way up the agitator so that there remains a substantial space into which the solution and oil are constantly sprayed.

In order to carry out the desired reaction a small quantity of air or oxygen is intro-.

duced into the oil through a line 13, controlled by valve 14, the air passing into the solution from a perforated coil 15 within the agitator 2. The air is thereby caused to agitate the liquid in the agitator and to secure both thorough commingling of the treating solution and oil and thorough contact between the air and oil or distillate. The excess air is taken off through a line 17 provided with a valve 16 and hence is preferablyv led to any desired form of gas absorber (not shown) by which any entrained vapors may be removed from the air.

The process as carried out by said apparatus is preferably continuous in operation but may also be operated by batch methods and moving air agitation or a combination of airwgitation and mechanical agitation.

en the process is carried out continuously the copper ammonia solution being of greater specific gravity than the petroleum distillate settles to the bottom-of the agitator 2 and is continually drawn ofi through pipe 19 and passed into tank 4, valve 18 and 20 being employed for regulating this withdrawal rate.

The treated distillate is preferablybontinuously withdrawn through a line 21, contolled by a valve 22 and passed into agitator 3. In the drawings the respective liquid levels of the petroleum distillate and copper ammonia solution are approximately shown. It will be observed that there are thus provided within the agitator 2 an air space above the level of any liquid, then a space in which agitation of the copper ammonia solution and petroleum distillate and air takes place,

below which is a portion of the treater in which the copper ammonia solution may settle from the pertoleum oiland the lower portion of the treater is occupied by settled copper ammonia solution. The treated distil' late is preferably withdrawn from the agitator 2 slightly above the top of such settled copper ammonia solution.

" Within the agitator 3 the treated distillate is preferably water washed by water entering line 23 controlled by valve 24 and sprayed into the treater from a spray 25. The liquid levels of the Water treated distillate should be maintained at approximately the relative height shown in the drawing. The treated and'washed distillate is withdrawn through line 29, controlled by valve 28 and passed into the tank 5 which receives the finished stock. The water in settling out of the petroleum distillate is drawn off to the sewer through line 27, controlled by the valve 26.

The copper ammonia solution may be used several times without impairing its eiiiciency.

Thereafter the copperv ammonia solution in tank 4 may be pumped back into the agitator 2 through line 31 controlled by valves and 32, passing into the treater 2 with fresh untreated distillate from line 10.

The treating solution of copper ammonia salt may be made in accordance with the following formula:

1 lb. of copper sulphate and A; gallon 26 B. ammonia per barrel of aqueous solution gallons).

This solution may, for example, be introduced into agitator 2 with the petroleum distillate at the rate of 5 barrels of solution per 100 barrels of distillate.

It is, of course, apparent that the strength of solution and the amount to be used may vary with the character of distillate being treated.

We have also discovered that when it is unvolume of highly diluted copper ammonia solution,'which has been previously aerated. Such solutionwill retain sufiicient oxygen for the reaction. In this case mechanical agitation would. generally be necessary to thoroughly commingle the petroleum distillate and treating solution.

It is understood that after treating the distillate with the copper ammonia solution until the distillate reacts negatively to the doctor test, the petroleum distillate may be further treated by acid, adsorptive clay or by other means to remove corrosion or gum forming constituents and improve the color of the product. The expense of such treatment necessary to produce a marketable prod-' uct is substantially reduced and in some cases the copper oxidizing operation followed by a mere decolorization with adsorptive clay 2oissuficient to produce a product which will meet all requirements.

While the method of treating petroleum distillates herein described is-well adapted for accomplishing the objects of the present invention, it is understood that the invention includes all such modifications and changes as come within the scope of the appended claims.

We claim:.

1. A. method of treating petroleum oil which comprises treating the oil with an aqueous solution of a copper salt containing dis solved oxygen.

2. A method of treating petroleum oil 7 which comprises treating the oil with an equeous solution of a copper ammonium salt containing dissolved oxygen.

3. A method of treating. petroleum oil which comprises adding to the oil a dilute 40 solution of cupric salt previously aerated so that said solution is substantially saturated with dissolved oxygen. 4. In a process of treating petroleum oil the step of contacting an aerated dilute aqueone solution of a catalytic cupric. salt with the oil. Y

Signed at El Segundo,- Calii, this 28th day of November, 1925. GEORGE J. ZISER. *JAMES H. OSMER. 

